Indoor Air sciences CSMI Practice Exam

Legionella is classified as which type of bacteria?

1. Gram positive fungi

2. Gram positive bacteria

3. Gram negative bacteria

4. Gram positive virus

The correct answer is: Gram negative bacteria

Legionella is classified as a type of Gram negative bacteria, which is important for understanding its characteristics and behavior. Gram negative bacteria are characterized by a thinner peptidoglycan layer in their cell wall, which is surrounded by an outer membrane. This structural composition can influence their pathogenicity, resistance to antibiotics, and the way they interact with host immune responses. The classification of Legionella as Gram negative is particularly relevant in the context of its modes of transmission and its environment. These bacteria are often found in water systems, such as those in buildings, hot tubs, and cooling towers. Understanding this classification helps in developing effective diagnostic and treatment strategies for infections like Legionnaires' disease, caused by Legionella. This classification also distinguishes Legionella from other groups of bacteria, such as Gram positive bacteria or fungi, which have different structural, functional, and ecological characteristics. For instance, Gram positive bacteria have a thick peptidoglycan layer and lack the outer membrane found in Gram negative bacteria, which can affect their vulnerability to certain antibiotics.